If you are moving it before it compleatly sets up, that could be your problem.
sdCowboyBen The Scotch 3M Super 77 is just like contact cement, just a sprayable version. I have worked for HD and Lowes in the paint department so I know what you are talking about. I am thinking squeegee since I own one. Or continue with my hand because you can feel the imperfections better. Thanks for the advice. Ben zstripe I use a wallpaper hanger smoothing brush and contact cement, brushed on. Got it in a kit back in the early 80's, when I wallpapered a couple rooms in My house....they still sell them, along with a seam roller. https://www.amazon.com/Industries-Paper-Smoother-Hanger-11930/dp/B000KKKYJM Take Care! Frank
The Scotch 3M Super 77 is just like contact cement, just a sprayable version. I have worked for HD and Lowes in the paint department so I know what you are talking about. I am thinking squeegee since I own one. Or continue with my hand because you can feel the imperfections better. Thanks for the advice.
Ben
zstripe I use a wallpaper hanger smoothing brush and contact cement, brushed on. Got it in a kit back in the early 80's, when I wallpapered a couple rooms in My house....they still sell them, along with a seam roller. https://www.amazon.com/Industries-Paper-Smoother-Hanger-11930/dp/B000KKKYJM Take Care! Frank
I use a wallpaper hanger smoothing brush and contact cement, brushed on. Got it in a kit back in the early 80's, when I wallpapered a couple rooms in My house....they still sell them, along with a seam roller.
https://www.amazon.com/Industries-Paper-Smoother-Hanger-11930/dp/B000KKKYJM
Take Care!
Frank
I know about the 77....I don't use it on large surface's because it is very easy to miss a spot with the spray or spots that You don't know are there, until it sets up, so when it does finally set-up, You'll get bubbles where the spray was thin and I believe that is what happened to You. When You brush it on, You can see whether it is thick or thin, in all area's.
I am not fond of 3M #77 because the time to adjust the backdrop is extremely short. To avoid bubbles (dry spots and air pockets), you need to work quickly.
The first thing to do is to perfectly align the dry surfaces by rehearsing your moves. Then spray the non-backdrop surface first, then the backdrop surface next, with a moist sponge in hand to smooth out the air pockets.
Rich
Alton Junction
You might be applying it wrong. Are you letting it sit after spraying, for about 30 seconds? As going from here http://www.instructables.com/id/Stick-together-How-to-properly-use-Super-77-spray/?ALLSTEPS the x second wait for tackyness is an important part of the process.
Thanks. All are options. I have been spraying with just a light touch on both surfaces and immediately using my hands to make sure there are no bubbles. This is done outside but I am in San Diego so the temp inside is the same temp outside, humidity too. It all looks pretty good until I bring it in and it gets bounced around a little before I get it up on the wall. I will try your suggestions and if I get the same results I will just use 3m double sided tape on the wall and make sure it is stretched.
mlehman How long are you letting the two surfaces stay open before joining them? I often slap stuff together after hitting it with 77, because it let's you shift things around briefly while still liquid. As the solvent evaporates, the stuff gets set. Maybe leaving the two pieces open for several minutes will allow more to evaporate and solve this problem? Also, using too much 77 could make this worse. Particularly if sparying both materials to be mated, a thin coat usually works and has fewer issues.
How long are you letting the two surfaces stay open before joining them? I often slap stuff together after hitting it with 77, because it let's you shift things around briefly while still liquid. As the solvent evaporates, the stuff gets set. Maybe leaving the two pieces open for several minutes will allow more to evaporate and solve this problem?
Also, using too much 77 could make this worse. Particularly if sparying both materials to be mated, a thin coat usually works and has fewer issues.
Mike Lehman
Urbana, IL
I bought Foamboard (3 x 5) specifically for glueing my backgrounds onto. I use 3M #77 and cover the back of the foamboard and seperately the backdrop. I had it all smothed out with no bubbles at all as I put it up on the wall. A day later it was full of bubbles again. I have tried to do this twice now.
What am I doing wrong? I need a better idea before I rip them off the foamboard and staple them onto the wall.